Thin but solid shell up to 2.5cm in length. It is white to brown in colour tending to be lighter when younger. The surface is sculptured with radiating ribs and concentric lines. When alive it has prominent orange tentacles.
Key identification features
- Fifty or more radiating ribs
- There is a prominent gape at the sides of the valves
- The shell is not symmetrical around the beak
Ecology and behaviour
This species prefers bottoms of coarse sand or gravel. The orange tentacles cannot be withdrawn potentially making it quite vulnerable to predation and as a result it often lives in a 'nest'. Thiscan be up to 25cm across and is knitted together using byssus threads. Filter feeds?
Distribution and status
LocalDistributed from the Lofoten Islands to the Iberian Peninsula and into the Mediterranean.